This invention relates to a keyboard musical instrument and, more particularly, to a keyboard musical instrument equipped with pedal mechanisms for artistic expression.
A grand piano, an upright piano and an automatic player piano are categorized in the keyboard musical instrument. These keyboard musical instruments have strings, and piano tones are generated through the vibrations of the strings. Pianists wish to bring on changes of the piano tones for artistic expression. A pianist brings on the change by prolonging the piano tone, and another pianist lessens the loudness by causing fewer than the normal number of strings to be struck or bringing the hammers nearer the strings. The tools for the artistic expression are pedal mechanisms incorporated in the grand/upright pianos. These pedal mechanisms are called as xe2x80x9csoft pedal mechanismxe2x80x9d, xe2x80x9cmuffler pedal mechanismxe2x80x9d, xe2x80x9cdamper pedal mechanismxe2x80x9d and xe2x80x9csostenuto pedal mechanismxe2x80x9d. The pianists selectively actuate the pedal mechanisms during the performance as described in Japanese Patent Publication of Unexamined Application (laid-open) No. 2-48695 and Japanese Utility Model Publication of Examined Application No. 58-25426. A standard upright piano is equipped with the soft pedal mechanism, the muffler pedal mechanism and the damper pedal mechanism. On the other hand, the soft pedal mechanism, the sostenuto pedal mechanism and the damper pedal mechanism are incorporated in a standard grand piano. Those pedal mechanisms are briefly described hereinbelow.
The soft pedal mechanism of the upright piano is connected to a hammer rail. Plural hammer rail felts are attached to the rear surface of the hammer rail, and hammers are resting on the hammer rail felts before the actuation of associated action mechanisms. The pianist is assumed to step on the soft pedal. The soft pedal mechanism advances the hammer rail toward the strings. The hammer rail rearward urges the hammers, and, accordingly, the gap between the hammers and the strings is decreased. When the pianist depresses the black/white key, the depressed key actuates the action mechanism. The jack escapes from the hammer, and the hammer starts free rotation toward the set of strings. Although the hammer strikes the strings, the intensity of impact is weaker than the normal intensity, because the strike takes place immediately after the escape. This results in that the strings vibrate softly, and the volume is lessened.
The muffler pedal mechanism is linked with a muffler rail. Muffler felts are attached to the muffler rail. When the pianist steps on the muffler pedal, the muffler felts are moved into the space between the strings and the action mechanisms. The depressed key gives rise to escape of the jack from the hammer, and the hammer starts the free rotation toward the strings. The strings are struck with the hammer. However, there is the muffler felt between the hammer and the strings. For this reason, the piano tone is softened.
The damper pedal mechanism of the upright piano is connected to a damper rod. The damper rod laterally extends in the vicinity of the array of damper levers. While the pianist does not exerts any force on the damper pedal, the damper rod is spaced from the damper levers, and the damper levers are selectively rotated by the depressed keys so as to space the damper head assemblies from the associated sets of strings. The pianist is assumed to step on the damper pedal. The damper rod urges all the damper levers so as to keep the damper head assemblies spaced from the sets of strings. The depressed key gives rise to the escape of the jack from the hammer, and the hammer strikes the associated set of strings at the end of the free rotation. The strings vibrate for generating the piano tone. When the pianist releases the depressed key, the black/white key starts to return to the rest position. Although the released key is spaced from the damper lever, the damper rod keeps the damper head assembly spaced from the set of strings. For this reason, the vibrations are continued, and the piano tone is prolonged.
The soft pedal mechanism of the grand piano is linked with action mechanisms/hammers. While the soft pedal is resting, the hammers are directly opposed to the sets of strings. All the strings of each set are struck by the associated hammer for generating the piano tone. However, when the pianist steps on the soft pedal, the action mechanisms laterally slide, and each of the hammers is opposed to the strings fewer than the normal number of strings. When the pianist depresses the associated black/white key, the depressed key actuates the action mechanism, and, thereafter, causes the jack to escape from the hammer. The escape gives rise to free rotation of the hammer toward the strings. The fewer strings are struck with the hammer, and vibrate for generating the piano tone at loudness smaller than the usual loudness.
The sostenuto pedal mechanism of the grand piano is linked with a sostenuto rod. The sostenuto rod laterally extends in the vicinity of the dampers. While the sostenuto pedal is resting, the dampers are free from the sostenuto rod, and the dampers are spaced from and brought into contact with the associated strings depending upon the key positions. The pianist is assumed to step on the sostenuto pedal after depressing the black/white key. The sostenuto rod keeps the damper head assembly spaced from the strings, and does not permit the damper head assembly to be brought into contact with the strings. Even though the pianist releases the depressed key, the damper head assembly remains spaced, and the piano tone is prolonged. Thus, the pianist individually prolongs the piano tone by means of the sostenuto pedal mechanism.
The damper pedal mechanism of the grand piano also keeps the damper head assemblies spaced from the sets of strings for prolonging the piano tones. The damper pedal mechanism is connected to a lifting rail laterally extending under damper levers. While the damper pedal is resting, the lifting rail remains spaced from the damper levers, and the damper head assemblies are spaced from and brought into contact with the sets of strings depending upon the key positions. The pianist is assumed to step on the damper pedal. The lifting rail pushes up all the damper levers, and causes the damper wires to space all the damper head assemblies from the sets of strings. A depressed key actuates the action mechanism, and gives rise to the free rotation of the hammer through the escape of the jack. The strings are struck with the hammer, and the strings vibrate for generating the piano tone. When the pianist releases the depressed key, the black/white key starts to return toward the rest position. Although the released key does not urge the damper lever, the lifting rail keeps the damper head assemblies spaced from the sets of strings, and the piano tone is prolonged. While the pianist is keeping the damper pedal depressed, all the piano tones are prolonged.
As will be understood, the pedal mechanisms independently bring on the changes for the artistic expression. Accordingly, each of the pedal mechanisms is independent of the other pedal mechanisms. In order to make the independent pedal mechanisms clear, description is made on the arrangement of the prior art pedal mechanisms.
FIGS. 1 to 6 show the prior art pedal mechanisms incorporated in the standard grand piano. The standard grand piano comprises a piano housing 1 and a pedal box 2. The pedal box 2 is hung from the piano housing 1 by means of a lyre block and a lyre post, and a soft pedal 3, a sostenuto pedal 4 and a damper pedal 5 are swingably supported by the pedal box 2. The soft pedal 3 and the damper pedal 5 project from the left side and the right side of the pedal box 2, and the sostenuto pedal 4 is located between the soft pedal 3 and the damper pedal 5. Three pedal rods 10, 11 and 12 are linked with the soft pedal 3, the sostenuto pedal 4 and the damper pedal 5, respectively, and extend from the pedals 3, 4 and 5 upwardly.
Various boards are assembled into the piano housing 1. One of the boards is a key bed 1a. A keyboard 1b includes black/white keys and a key frame 1c, and is mounted on the key bed 1a. Action mechanisms 1d are linked with the black/white keys of the keyboard 1b. Hammer assemblies 1e are rotatably supported by a shank flange rail 1f, which in turn is supported by action brackets 1g. The hammers 1e are linked with the action mechanisms 1d, respectively. Strings 1h are stretched over the hammers 1e, and are to be struck with the hammers 1e. Dampers 1i are linked with the rear portions of the black/white keys, and are spaced from and brought into contact with the associated strings 1h. 
When a pianist depresses one of the black/white keys, the front portion of the depressed key is sunk, and, accordingly, the rear portion is lifted so as to actuate the associated action mechanism 1d. The rear portion of the depressed key pushes the damper 1i upwardly, and the damper 1i is spaced from the associated strings 1h. Then, the strings 1h get ready for vibrating. When the jack (not shown) escapes from the hammer 1e, the hammer 1e is driven for free rotation toward the strings 1h. The strings 1h are struck with the hammer 1e at the end of the free rotation, and vibrates for generating the piano tone. The hammer 1e rebounds on the strings 1h, and returns to the action mechanism 1d. After the generation of the piano tone, the pianist releases the depressed key, and the rear portion of the released key is sunk. The released key allows the damper 1i to be brought into contact with the strings 1h, and the vibrations are absorbed. Thus, the component parts 1b/1d/1e/1g/1h are sequentially activated along the well-known process for generating the piano tone.
The prior art pedal mechanisms includes the soft/sostenuto/damper pedals 3/4/5 and the pedal rods 10/11/12 as described hereinbefore. The pedal rods 10/11/12 are connected to the soft/sostenuto/damper pedals 3/4/5, respectively, and are vertically moved by means of the associated pedals 3/4/5. Three link works are connected between the pedal rods 10/11/12 and the key frame 1c, a sostenuto lift rod 1j and a lifting rail 1k, respectively.
As will be better seen in FIG. 3, the link work of the soft pedal mechanism includes a pedal lever 6, a bearing unit 13, a pin 14 and a stopper 20. The pedal rod 10 is held in contact with the left end portion of the pedal lever 6. The right end portion of the pedal lever 6 is connected to another lever, and is supported by the bearing unit 13 through the pin 14. The stopper 20 sets a limit to the moving range of the pedal lever 6 (see FIG. 4). The stopper 20 and the bearing unit 13 are directly attached to the lower surface of the key bed 9.
The link work of the sostenuto pedal mechanism includes pedal levers 7, a bearing unit 13, a pin 14, a return spring 15 (see FIG. 5) and a stopper 20. The pedal levers 7 are connected to each other. The pedal rod 11 is held in contact with the right end portion of the pedal lever 7, and the left end portion of the other pedal lever 7 is connected to the sostenuto lift rod 1j. The pedal lever 7 is supported by the bearing through the pin 14, and the return spring urges the pedal lever 7 downwardly. The stopper sets a limit on the moving range of the pedal lever 7. The bearing unit 13 and the stopper 20 are directly attached to the lower surface of the key bed 9, and the return spring 15 is inserted between the lower surface of the key bed 9 and the pedal lever 7.
The link work of the damper pedal mechanism includes a pedal lever 8, a bearing unit 13, a pin 14, a return spring 15 (see FIG. 6) and a stopper 20. The pedal rod 12 is held in contact with the right end portion of the pedal lever 8, and a vertical rod is fixed to an intermediate portion of the pedal lever 8. The vertical rod is held in contact with the lower surface of the lifting rail 1k. The pedal lever 8 is supported by the bearing 13 through the pin 14, and the stopper sets a limit to the moving range of the pedal lever 8. The return spring 15 urges the pedal lever 8 downwardly. The bearing unit 13 and the stopper 20 are directly attached to the lower surface of the key bed 9, and the return spring 15 is inserted between the lower surface of the key bed 9 and the pedal lever 8.
Thus, the three link works are directly attached to the lower surface of the key bed 9, and the force exerted on the soft/sostenuto/damper pedals 3/4/5 is independently transmitted through the three link works to the key frame 1c, the sostenuto lift rod 1j and the lifting rail 1k. 
FIG. 7 shows the prior art pedal mechanisms incorporated in the standard upright piano. A soft pedal, a muffler pedal and a damper pedal are designated by reference numerals 25, 26 and 27, respectively. Various boards are assembled into a piano housing. A bottom board 28a and a bottom sill 28b form parts of the piano housing. The soft pedal mechanism, the muffler pedal mechanism and the damper pedal mechanism are installed inside the piano housing, and the soft pedal 25. The sostenuto pedal 26 and the damper pedal 27 are rotatably supported by brackets 29, respectively, and the brackets are fixed to the upper surface of the bottom board 28a. Holes are formed in the bottom sill 28b, and the soft pedal 25, the muffler pedal 26 and the damper pedal 27 project through the holes to the outside of the piano housing.
The soft pedal 25 is connected at the rear end portion thereof to the right end portion of a soft pedal lever 30a, which in turn is connected at the left end portion to a lower end of a soft pedal rod 31. The soft pedal lever 30a is swingably supported by a bearing unit 37, and a coil spring 38 urges the soft pedal lever 30a upwardly. The bearing unit 37 is fixed to the upper surface of the bottom board 28a, and the coil spring 38 is inserted between the upper surface of the bottom board 28a and the lower surface of the soft pedal lever 30a. 
The muffler pedal 26 is connected at the rear end thereof to a link work. The link work includes muffler rods 33 and muffler link levers 34, and the muffler 36 is connected to the link work.
The damper pedal 27 is connected at the rear end thereof to the right end portion of a damper pedal lever 30b, which in turn is connected at the left end portion to the lower end of the damper pedal rod 32. The damper pedal lever 30b is swingably supported by a bearing unit 37, and a coil spring 38 urges the damper pedal lever 30b upwardly. The bearing unit 37 is fixed to the upper surface of the bottom board 28a, and the coil spring 38 is inserted between the upper surface of the bottom board 28a and the lower surface of the damper pedal lever 30b. Thus, the pedal mechanisms of the standard upright piano are directly supported by the bottom board, and the force exerted on the soft/muffler/damper pedals 25/26/27 is independently transmitted through the link works.
Another prior art bottom board is disclosed in Japanese Patent Application of Unexamined Application No. 7-295551. The bottom board 28a and the bottom sill 28b are integrated into the bottom board disclosed in the Japanese Patent Publication of Unexamined Application. Three holes are formed in the narrow portion corresponding to the bottom sill 28b, and brackets are cut out in the wide portion corresponding to the bottom board 28a. The brackets serve as the brackets 29 and the parts of the bearing units 38. Moreover, spring seats are formed on the wide portion. The bottom board disclosed in the Japanese Patent Publication of Unexamined Application forms a piano housing together with other boards. Pedals and link works are assembled with the brackets, and the springs are inserted between the spring seats and the pedal levers.
A problem is encountered in the prior art pedal mechanisms in the assembling work. As described hereinbefore, each of the three pedal mechanisms is independent of the others. The prior art pedal mechanisms of the grand piano are directly supported by the key bed 9, and the prior art pedal mechanisms of the upright piano are directly supported by the bottom board 28a. Namely, the three pedal mechanisms are attached to the same board member. This means that a factory worker is expected to assemble the component parts into the three pedal mechanisms individually. The piano housing is completed before the assemblage of the pedal mechanisms. The factory worker gets into the space under the key bed 9, and starts the assembling work. The factory worker fixes the bearings 13 to the lower surface of the key bed 9 together with the pedal levers 6, 7 and 8. The factory worker further fixes the stoppers 20 to the lower surface of the key bed 9, and inserts the return springs 15 between the key bed 9 and the pedal levers 7/8. The space under the piano housing is so narrow that the factory worker feels the assembling work uncomfortable. The assembling work requires much time, and work efficiency is low. This results in a high production cost. Although the component parts are assembled into the three pedal mechanisms over the bottom board 28a, the bottom board 28a has been already assembled into the piano housing, and the working space is narrow. A factory worker fixes the brackets 29 and the bearing units 37 onto the bottom board 28a, and assembles the soft/muffler/damper pedals 25/26/27 and the pedal levers 30a/30b with the brackets 29 and the bearing units 37. Thereafter, the factory worker inserts the coil springs between the bottom board 28a and the pedal levers 30a/30b, and connects the pedal rods 31/32/33 to the pedal levers 30a/30b and the muffler pedal 26. The work efficiency is also low, and assembling work requires much time. As a result, the production cost is increased.
Although the factory worker does not need to fix the brackets 29 and the bearing units 37 on the bottom board disclosed in Japanese Patent Publication of Unexamined Application No. 7-295551, the pedals 25/26/27, the pedal levers 30a/30b and the pedal rods 31/32/33 are to be assembled after the complication of the piano housing, and the work efficiency is also low.
It is therefore an important object of the present invention to provide pedal mechanisms, which are easily assembled into a keyboard musical instrument.
It is also an important object of the present invention to provide a keyboard musical instrument, which is reduced in production cost.
To accomplish the object, the present invention proposes to assembly pedal mechanisms in a unit.
In accordance with one aspect of the present invention, there is provided a pedal system incorporated in a keyboard musical instrument comprising a base plate having a major surface and to be attached to a housing of the keyboard musical instrument, plural foot pedals swingably supported by the base plate, and plural link works provided on the major surface, movably supported by the base plate and connected to the plural foot pedals, respectively.
In accordance with another aspect of the present invention, there is provided a keyboard musical instrument comprising a keyboard having plural keys respectively assigned notes of a scale and selectively moved, plural sets of strings respectively associated with the plural keys and independently vibrating for generating tones at the notes, plural vibration generating mechanisms respectively connected to the plural keys for generating vibrations in the strings of the plural sets when the plural keys are selectively moved, a housing for accommodating the plural sets of strings and the plural vibration generating mechanisms and supporting the keyboard in such a manner as to expose the keyboard to the player, and plural pedal mechanisms linked with the plural vibration generating mechanisms, selectively actuated for changing attributes of the tones and including a base plate and component parts assembled into a unit attached to the housing.